Histological study of the effect of transient neonatal hypothyroidism on the testes of albino rats

ABSTRACT

Recognition and treatment of childhood hypothyroidism now is very essential to avoid many problems. So, the ministry of health in Egypt added routine estimation of thyroid hormones in the first week of neonatal life with the programs of vaccination for every newborn. The aim of this work was to study the effect of transient neonatal hypothyroidism on the growth of testes during different periods of postnatal testicular development. In this study hypothyroidism was induced in neonates by giving of propylthiouracil [PTU] to the lactating mothers from the day of parturition till weaning [24 days postpartum]. Some mothers were left without treatment and used as control. Thirty male pups were used and divided into two groups [control and experimental] each 15 animals. Their weights were determined at days 15, 25 and 120 then they were sacrificed and testes weights were estimated. One testis was processed for light microscopical study and the other was processed for transmission electron microscopical study. The results revealed that, transient neonatal hypothyroidism induced decrease in neonatal and adult body weights and also decrease in neonatal testis weight. There was very high significant increase in the adult testis weight which was accompanied histologically by apparent increase in Sertoli cells number, Leydig cells and interstitial connective tissue. There were Sertoli cells with immature nuclei in 25 days old animals receiving PTU but not in age-matched control. Sertoli cell tight junction formation was also delayed in treated animals as compared with the control. That mean there were delay of maturation of Sertoli cells with delay of the maturation and proliferation of other testicular components in experimental groups. The results indicate early critical influence of thyroid hormones on the growth and development of testes as reproductive organs